Sewing goods and the like tentering frame and assembly device therefor



May 13, 1969 E. BECKER E SEWING GOODS AND THE] LIKE TENTERING FRAME AND ASSEMBLY DEVICETHEREFOR Filed Dec. 20, 1966 v Sheet of s Wyn/raps:

Ernsf EEC/(El? Karl N02 mm RAT/l I A rrae/vE/ May 13,1969 E, BECKER- ET AL 3,442,537

SEWING GOODS AND THE LIKE TENTERING FRAME AND ASSEMBLY DEVICE THEREFOR Filed Dec. 20, 1966 Sheet 2 of s ill) Arm/away May 13; 19 9 acK ER ET AL 3,443,537.

Filed Dec. 20, 1966 SEWING GOODS AND THE LIKE TENTERING FRAME AND ASSEMBLY DEVICE THEREFOR Sheet 3 of s 5 i L 34 iv 3 it}: :2 7 ill i l 23 T Q\ PI Q .29 2a 22 P5 P31 s 25 A 8 35 3'0 36 C:T l F I .INVENMRSI Erns/ 550m? War/4 N072 A 7717/? NE y llnited States Patent 3,443,537 SEWING GOODS AND THE LIKE TENTERING FRAME AND ASSEMBLY DEVICE THEREFOR Ernst Becker, Darmstadt, Germany, and Karl Notz, Kulmbach, Upper Franconia, Germany, assiguors to Quick-Rotan Becker & Co., Darmstadt, Germany, a firm of Germany Filed Dec. 20, 1966, Ser. No. 603,208 Claims priority, application germany, Dec. 22, 1965, 8

Int. Cl. D05b 21/00 U.S. Cl. 112103 7 Claims ABSTRACT OF THE DISCLOSURE A workpiece tentering frame comprises a lower and upper clamping plate having contours conforming with the contour of a workpiece to be clamped therebetween by a plurality of permanent magnets attracting one plate against the other in the aligned position, with the workpiece having a constant edge zone projecting beyond the edges of the plates. The frame and workpiece are assembled by means of an assembly device comprising a base plate having secured thereto, in the order named, first and second assembly plates having recesses conforming, respectively to the contours of the lower clamping plate and the workpiece. A third assembly plate may be provided hingedly connected to the second plate and having a recess conforming to the contour of the upper clamping plate.

The present invention relates to a sewing goods and the like tentering frame, especially, though not limitatively, for use in conjunction with an automatic sewing machine including means for moving said frame and a workpiece mounted therein past the stitch-forming tools of said machine and along a predetermined sewing path or pattern, such as by means of a moving control stencil having a configuration defining said path and operably connected with said frame.

There are already known devices of the foregoing type embodying a tentering frame comprising a lower clamping plate of non-magnetic material and resting upon the sewing table or bed of a sewing machine and an upper clamping plate preferably hingedly mounted upon said lower plate and consisting of magnetically conducting material. Mounted within the sewing table is at least one magnet which the upper clamping plate constitutes an armature or magnetic conducting path. In use, the sewing goods or workpiece is inserted between the plates in the open position, whereupon the upper plate is swung down upon the lower plate to firmly hold the workpiece between said plates. The frame containing the workpiece and positioned upon the sewing table with the aid of suitable index mark or the like, is coupled with a cross-slide being in turn connected to and operated by a stencil representing a desired sewing path or pattern and engaged by a friction driving roller rotating about a vertical axis, to operate or advance the stencil and with it said frame along said path.

In operation, after the tentering frame has been properly positioned upon the sewing table of the machine, the magnet within said table is energized, to attract the upper magnetic plate towards the table and to thus firmly clamp the work beween both clamping plates. Finally, both the stencil drive and sewing machine are set in motion, to automatically sew a stitching pattern represented by said stencil upon the work being operated on.

Arrangements of the foregoing type have been found to operate satisfactorily in conjunction with sewing goods in the form of relatively small and thin workpieces having 3 ,443,537 Patented May 13, 1969 a simple shape or configuration and consisting of an easily sewable material, whereby to enable a secure positioning or mounting of the work between the plates with sufficient accuracy and by a relatively small clamping force, to prevent inadmissible displacements of the work relative to the frame and, in turn, deviations from the desired stitching path in the course of a sewing operation. On the other hand, in the case of workpieces of relatively greater thickness, of relatively complex stitching patterns, or of less easily sewable material, substantially greater clamping forces are required between the plates of the frame. While there exists principally no difficulty in increasing the magnetic force of the magnet or magnets mounted in the sewing table, an upper limit is soon reached due to the fact that the displacement of the frame by the stencil relative to the stationary sewing table is opposed by the magnetic force, on the one hand, and that it is desirable, if not necessary, to maintain the driving force by the stencil below a certain limit on the other hand, in the interest of ensuring an adequate degree of accuracy of both the stencil and cross-slide design and operation.

Accordingly, an important object of the present invention is the provision of a sewing goods or the like tentering frame of the referred to type, specially for use in connection with automatic sewing path copying devices or machines, whereby the foregoing and related difiiculties and defects are substantially eliminated or minimized.

A more specific object of the invention is the provision of a tentering frame of the referred to type which will make it possible, even with the use of relatively small driving forces for displacing said frame and in case of workpieces of any complex shape, size and/or consisting of material being difficult to sew, to transfer the contour configuration or pattern of the stencil to the work with a relatively high degree of precision or accuracy. Yet another object of the invention is the provision of a simple assem- 'bly device to ensure accurate alignment of the workpiece within the tentering frame preparatory to the mounting of the frame upon the sewing machine.

The invention, both as to the foregoing and ancillary objects, as well as novel aspects thereof, will be better understood from the following detailed description, taken in conjunction with the accompanying drawings forming part of this specification and in which:

FIG. 1 is a plan view of a tentering frame shown mounted in its assembly frame, both said frames constructed in accordance with the principles of the invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1, showing the tentering frame and workpiece after removal from the assembly frame;

FIG. 3 is a fragmentary section of the tentering frame per se, shown on an enlarged scale and taken on line 3-3 of FIG. 1;

FIG. 4 is an elevational view of automatic sewing apparatus embodying a tentering frame according to the invention;

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a fragmentary view, shown on a greater scale, of FIG. 4; and

FIG. 7 is a side view of FIG. 6 as viewed in the direction of the arrow 7.

Like reference numerals denote like parts and elements throughout the different views of the drawings.

With the foregoing objects in view, the invention involves generally the provision of a tentering frame of the referred to type having at least one of its clamping plates of non-magnetic material fitted with a plurality of permanent magnets forming magnetic paths with the cooperating clamping plate of the frame being constructed of magnetic material. Such a construction makes it possible to dispense with a magnet or magnets mounted within the sewing table of the machine, that is, outside of the tentering frame proper. As a consequence, according to the present invention both plates are attracted towards one another and clamped against the intervening workpiece directly rather than indirectly by attraction of the upper plate against the sewing table, as in the case of the prior art devices. Expressed in other words, the magnetic attracting field or fields according to the present invention are confined to the space intervening between the clamping plates proper, whereby to enable an increase of the clamping force to any desired value without deleterious effect upon or interference with the stencil drive or operation. Besides, the clamping force may now be simply controlled or varied within different areas of the frame or sections of the sewing path, such as by the use of magnets of different size or strength and/or by the variation of the spacing or number of magnets used, to suit varying stitching path configurations and other existing operating conditions or requirements. Besides, an increased clamping effect may be achieved in this manner at the areas subjected to especially heavy forces during operation such as along the curved sections of the sewing path or contour of the tentering frame, by the provision of a greater number of magnets or by varying the strength of the magnets compared with the straight or linear sections of said path.

Another advantage of the invention consists in the greatly limited area of the magnetic field or force distribution, that is, the area covered by the tentering frame only, compared with the conventional devices requiring a magnetic field extending over a substantial area of the sewing table.

According to the preferred embodiment of the invention, the lower clamping plate consists of magnetic material and a plurality of permanent magnet elements are mounted adjacent to and along the outer edge or contour of the upper non-magnetic clamping plate. The latter is advantageously fitted with a depending peripheral flange following the contour of the plates and having a lower serrated edge engaging the workpiece in the immediate vicinity of the sewing path or zone, to thereby ensure a secure and efficient clamping or mounting of the work. Besides, the flange acts as a reinforcing or stiffening means, whereby to allow of a construction of the upper clamping plate from relatively thin or sheet material, while the serrated lower edge of the flange greatly contributes to the positioning or fixation of the workpiece within the tentering frame.

Inasmuch as deviations from the predetermined sewing path, aside from being due to displacements of the workpiece relative to the clamping plates during operation or movement of tentering frame, may furthermore be caused by an incorrect initial positioning or alignment of the plates and intervening workpiece, there is provided, in accordance with a further feature of the invention, an assembly frame or device fitted with suitable abutments, guide or index pins or the like, to afford an expeditious and automatic alignment of the plates relative to the workpiece, preparatory to the mounting or coupling of the tentering frame and workpiece with the stencil or the like drive mechanism of the automatic sewing machine.

The assembly frame advantageously consists of a plurality of superposed assembly or positioning plates provided with cut-outs or recesses which at least partially complementarily conform with the contours of the clamping plates and workpiece, respectively. Where one of the clamping plates is hingedly connected to the other clamping plate, that is, where the sewing path may encompass a limited peripheral portion only of the plates, the assembly frame may consist simply of a base plate, a first or lower assembly plate secured thereto and having a recess conforming with the contour of the lower clamping plate, and a second or upper assembly plate superposed upon and secured to said first assembly plate and having a recess conforming with the contour of the workpiece to be mounted or clamped.

On the other hand, where both clamping plates are separate or disconnected from one another, that is, where a closed pattern or seam may be sewn around substantially the entire periphery of the plates, as shown by the drawing, an additional third assembly plate is required for the positioning of the upper clamping plate, said third assembly plate having a recess which conforms with the contour of said upper clamping plate and being advantageously hingedly connected to the composite unit or subassembly comprised of said base and said first and second assembly plates.

In the use of a device of the foregoing type, the upper assembly plate is at first swung open and the lower clamping plate and workpiece inserted in the assembly frame, whereby the clamping plate and workpiece will be automatically aligned in the proper relative position by the corresponding recesses or abutment elements of the assembly plates. The upper assembly plate is then closed and the upper clamping plate inserted in its turn in the recess of the former. Upon renewed opening of the frame by upwardly swinging the upper assembly plate, the clamping plates together with the intervening workpiece firmly clamped therebetween by the magnetic attracting forces may be bodily removed or lifted from the assembly frame for coupling with or connection to the cross-slide control mechanism of the sewing machine.

According to an improved feature of the invention, the upper assembly plate consists of two or more parts being separately hinged to or otherwise connected with the assembly frame, in the manner as will become more apparent from the following description in reference to the drawings.

The assembly frame may be advantageously permanently mounted upon the sewing machine by means of a bracket or any other suitable supporting means. As a consequence, it becomes possible for the operator to assemble or prepare one frame, while the machine loaded with another frame is in operation.

Where the assembly frame is mounted above the stencil of the automatic sewing device, it acts as a protection by preventing unauthorized interference with the stencil control or operation.

The tentering frame may be fitted with suitable releasable coupling means for temporarily connecting the same with the stencil-cross-slide or the like operating mechanism, a preferred drive and coupling arrangement being shown and described by our copending patent application Ser. No. 603,303, filed on even date herewith and entitled Automatic Sewing Path Copying Device for Sewing and the Like Machines, the disclosure of which application is hereby embodied in the instant application by reference.

According to said copending application, the upper clamping plate of the tentering frame is fitted with releaseable coupling means adapted to effect a coupling of the frame with the coupling member of the cross-slide or the like control mechanism. Such coupling means, while providing a rigid connection between the tentering frame and the stencil or the like control device, allow of an instant and expeditious exchange of the frames, especially in mounting a previously loaded frame upon the termination of a sewing cycle.

Where the coupling means connecting the tentering frame with the cross-slide or the like drive crosses or intersects the sewing path or zone, that is, where a seam is to be sewn substantially encompassing the entire periphery of the frame, suitable by-pass or temporary release means may be provided, as shown by the accompanying drawings and further described by the afore-mentioned copending application.

According to a preferred embodiment of the releasable coupling means as shown by the accompanying drawings, the coupling element or elements of the tentering frame are in the form of ball-pointed coupling rods adapted to engage suitable coupling slits or recesses in the cooperating coupling members connected with the cross-slide or equivalent control device.

Referring more particularly to FIGS. l3, the tentering frame shown comprises a lower clamping plate 1 and an upper clamping plate 2 between which is inserted the sewing goods in the form of a fabric or the like workpiece 3. The outer contours of the plates 1 and 2 correspond with or follow the sewing path or pattern to be produced. Besides, the device shown is of the special type having the edge of the workpiece 3, shown in the form of a glove for purposes of illustration, projecting beyond the contour of the frame for edge-stitching or seaming by the stitchforming tools (needle 39, FIG. 6) of a sewing machine, in the manner well known and readily understood.

The lower flat clamping plate 1 consists of magnetically conducting material (iron, cobalt, etc.), while the upper plate consisting of non-magnetic material is advantageously formed, in the example shown, with a depending peripheral flange 4 following the contour of the frame and having a serrated or otherwise roughened edge engaging the workpiece 3 in the clamping position, as more clearly shown in FIG. 3. A number of permanent magnet elements 6 mounted in inverted cup-shaped supports 7 fast on plate 2 are suitably distributed over the area of the latter, the distribution of said magnets being advantageously such as to provide a high clamping pressure at or within the stitching zone proper being especially subjected to reactive forces in the course of a sewing operation. This latter object may be achieved simply by so distributing or positioning the magnets 6 along a line or pattern at least in part conforming with the contour of the frame, and/or by varying the spacing distance between the magnets, as shown in FIGS. 1 and 5.

The assembly frame or device 8 for the tentering frame, FIGS. 1 and 2, comprises a base plate 9, a lower assembly or positioning plate 10, a central assembly or positioning plate 11, and an upper two-part assembly or cover plate 12, 13. Plates 9, 10 and 11 are rigidly connected with each other, while the parts 12 and 13 of the cover plate are totatively connected to the subassembly or composite unit consisting of plates 9, 10, 11 by means of hinges 14 and 15, respectively. Assembly plates 10, 11 and 12, 13 are formed with inner recesses or cut-outs at least in part conforming, respectively, to the contour configuration of the lower clamping plate 1, the workpiece 3 and the upper clamping plate 2. Besides, the thickness of the plates of the assembly frame corresponds respectively to the thickness of clamping plate 1, workpiece 3 and clamping plate 2.

As can more clearly be seen from FIG. 1, the parts 12 and 13 of the upper assembly plate are advantageously in the form of narrow strips having inner contours which partially conform to the contour of the upper clamping plate 2. The lower and central plates 10 and 11 may be similarly designed or shaped, that is, such as not to engage the entire edges of the lower clamping plate 1 and workpiece 3, respectively, or to provide simple guides or abutments only for effecting a proper alignment of the parts, in a manner readily understood, the essential object or purpose of the assembly frame being the relative alignment and fixation of plates 1 and 2, on the one hand, and of the workpiece 3, on the other hand.

In use, after swinging upwardly and outwardly the cover plates 12 and 13, the lower clamping plate 1 is inserted in the cut-out of the assembly plate 10 such as to engage the base plate 9 of the assembly frame. The workpiece 3 is then inserted in its turn in the central assembly plate 11, the proper positioning relative to plate 10 being ensured by the cut-out or recess of plate 11. Finally, the two cover parts 12 and 13 are returned to the closed position shown in the drawing and the upper clamping plate 2 inserted between the parts 12 and 13, to result in the final assembly of the parts as shown in FIGS. 1 and 2.

As a consequence, the lower clamping plate 1 forms a magnetic conducting path or armature for the permanent magnets 6 of the upper clamping plate 2, in such a manner as to mutually attract plates 1 and 2 towards one another and to firmly clamp the workpiece 3 between plate 1 and the toothed edge of the flange of plate 2, as more clearly shown in FIG. 3. Renewed opening of the cover plates 12, 13 will then enable removal or lifting out of the entire tentering frame unit comprising the plates 1, 2 and the workpiece 3 clamped therebetween by the magnetic force of the magnets 6, for subsequent use of the frame or mounting upon an automatic sewing machine, in the manner further described in the following. In order to facilitate the removal of the frame, the upper clamping plate 2 is shown fitted with a knob or operating handle 16.

In order to removably connect the tentering frame 1, 2 with the mechanism controlling the sewing path or pattern of the machine, there are provided, according to the example shown for the purposes of illustration, a plurality of coupling elements 17, 18 and 19 afiixed to the upper clamping plate 2 and terminating in ball-pointed coupling rods 20' adapted to engage corresponding coupling slits or sockets 21 provided in the cooperating coupling members 22, 23, 24, respectively, (see also FIGS. 5 and 6) being supported by a profiled rail-shaped operating member or carrier 25 of inverted U-shaped crosssection of a cross-slide mechanism. The members 22, 23, 24 are pivotally mounted upon the carrier 25 about an axis parallel to the longitudinal carrier axis and fitted with suitable return springs 26, to normally urge the same into a substantially horizontal position, as shown by the drawing. The carrier 25 is in turn mounted upon and in relatively displaceable relation to a guide rail 28 forming the cooperating cross-slide operating member, as indicated by the double arrow 27 in FIG. 5, rail 28 being in turn slidably mounted in a direction at right angle to the movement of the carrier 25, upon the frame or support of the machine, as indicated by the double arrow 31. The mounting means of rail 28 comprise a pair of guide plates 29, 30' afiixed to the opposite ends of the rail end engaging corresponding vertical guide slots 32 and 33, respectively in the sewing plate or table 34.

Further connected with the carrier 25, by way of brackets 35, 36 is a stencil 37 arranged for operation or displacement within the plane of the table 34 and along a desired sewing path by the aid of a friction roller drive 38, in such a manner as to simultaneously cause the tentering frame 1, 2, or edge zone of the workpiece 3, to be displaced or moved past the stitching tool or needle 39, FIG. 7, of a stationary sewing machine 40 mounted upon the table 34. Secured to the front or head of the machine 40, in proximity to the needle 39, is a release member or cam 41 adapted to cooperate with the coupling members 22, 23, 24 in the manner to be described presently. The assembly frame may be advantageously mounted upon a supporting bracket 42 secured to the table 34, as shown in FIG. 4.

In use, the clamping frame 1, 2 holding the workpiece 3 is removed from the assembly frame and coupled with the carrier 25 by engaging the coupling rods of the elements 17, 18, 19 with the slits in the members 22, 23, 24, respectively. The carrier 25 and with it the frame 1, 2 are then manually operated to the starting position as shown in FIG. 5, whereupon is started the drive (not shown) of the rollers 38. As a consequence, the stencil 37 is continuously moved along a path conforming with the desired sewing path or pattern by the rollers 37 engaging the edge of the stencil, to in turn cause the frame 1, 2 and with it the projecting edge zone of the workpiece 3 to be passed under the needle 39, in a manner readily understood by those skilled in the art.

With specific reference to the device shown by the drawings as applied to the stitching of gloves, there is advantageously sewn, beginning from the starting position shown, at first the upper longitudinal seam portion followed by the finger portions of the glove. In continuing the stitching of the lower edge portion of the glove according to FIG. 5, the cam 41 engages successively and in the order named the coupling members 24, 23, 22, whereby the pointed end 43 of the cam temporarily engages said members, as shown more clearly for the member 23 in FIG. 3, in such a manner as to displace the members 22, 23, 24 along the cam surface and in an upward direction, to thereby enable the tentering frame to freely pass the stitching tool or needle 39 of the sewing machine. While one of the members is thus temporarily deflected or decoupled, the coupling between the tentering frame and the carrier 25 is maintained by the remaining members, that is, by the members 22 and 24 during deflection of the member 23, as shown in FIG. 7, and similarly for the other coupling members, in a manner readily understood. Upon passage past the stitching tool, the coupling members, being released from the cam 41, are returned into the coupling position by the action of the springs 26 by the ball-shaped coupling rods 20 of the corresponding coupling elements 17, 18, 19 re-entering the corresponding slits 21 of the coupling members. By an arrangement of this type, with the coupling members 22, 23, 24 being designed in the form of trap doors or by-pass devices, it is possible to edge seam or stitch a substantially closed pattern or path, like the seam involved in the sewing of gloves in the case of the example illustrated by the drawings.

In the foregoing the invention has been described in reference to a specific illustrative device. It will be evident, however, that variations and modifications, as well as the substitution of equivalent parts or elements for those shown for illustration, may be made without departing from the broader purview and spirit of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than in a restrictive sense.

We claim:

1. The combination with a tentering frame for a sewing and the like fiat workpiece of predetermined configuration to be operated on along its edge zone by a sewing or the like machine, said frame including a lower clamping plate consisting of magnetic materials and having a contour configuration conforming with the contour of said workpiece, an upper clamping plate of non-magnetic material having a size and configuration equal to said lower clamping plate, and a plurality of permanent magnets mounted upon and distributed over said upper clamping plate, to firmly clamp said workpiece placed between said plates, said plates having a size less than said workpiece, to cause a constant edge zone of the workpiece aligned with and clamped between said plates to project beyond the registering edges thereof; of an assembly device for said frame comprising in combination:

( 1) a base plate,

(2) a first assembly plate secured thereto and having a first recess at least partially complementarily conforming with the contour of said lower clamping plate, to position said lower clamping plate upon insertion in said recess, and

(3) a second assembly plate secured to said first clamping plate and having a second recess at least partially complementarily conforming with the contour of said workpiece, to position said workpiece upon said lower clamping plate by insertion in said second recess.

2. In a tentering frame assembly device as claimed in claim 1, including a third assembly plate hingedly connected to the unit formed by said base plate and said first and second assembly plates, said third assembly plate having a recess at least partially complementarily conforming with the contour of said upper clamping plate.

3. In a tentering frame assembly device as claimed in claim 2, said third assembly pate consisting of two relatively narrow strip-like members, and means hingedly connecting each of said members to one of the opposite edges of said unit.

4. In a tentering frame assembly device as claimed in claim 11, including a handle upon said upper clamping plate.

5. The combination with a tentering frame for a sewing and the like flat workpiece of predetermined configuration to be operated on along its edge zone by a sewing or the like machine, said frame including a lower clamping plate having a contour conforming with the contour of said workpiece, an upper clamping plate having a size and contour equal to said lower clamping plate, and permanent magnetic means operably associated with said plates, to firmly clamp said workpiece therebetween in the superposed position of the plates by magnetic attraction, said plates having a size less than said workpiece, whereby to cause a constant edge zone of the workpiece aligned with and clamped between said plates to project beyond the registering edges thereof; of an assembly device for said frame comprising in combination:

(1) a base plate,

(2) a first assembly plate secured thereto and having a first recess at least partially conforming with the contour of said lower clamping plate, and

(3) a second assembly plate secured to said first assembly plate and having a recess at least partially conforming with the contour of said workpiece.

(4) whereby to position said first clamping plate and workpiece in proper superposed and aligned relation by insertion in said first and second recess, respectively.

6. In a tentering frome assembly device as claimed in claim 5, including a third assembly plate hinged connected to said second assembly plate, said third assembly plate having a recess at least partially conforming with the contour of said upper clamping plate.

7. A tentering frame for a workpiece of predetermined configuration to be operated on along a path parallel to the edge thereof comprising in combination:

(1) a first clamping plate consisting of magnetic material and having a contour conforming with the contour of a workpiece to be operated on,

(2) a second clamping plate similar to said first plate and consisting of non-magnetic material,

(3) said plates having a size smaller than the workpiece, to cause a constant edge zone of the workpiece aligned with and clamped between the plates to project beyond the edge of the plates in the registry position, and (4) an array of permanent magnets mounted upon said second plate adjoining to and at least partially following the contour of said plates.

References Cited UNITED STATES PATENTS 2,145,060 1/1939 Stroop. 3,097,617 7/1963 Reid et a1. 3,172,379 3/1965 Light. 3,174,447 3/1965 Bono.

ALFRED R. GUEST, Primary Examiner. 

